Update to newer version 1.6.6.

Changes:

- BUG/MAJOR: fix listening IP address storage for frontends
- BUG/MINOR: fix listening IP address storage for frontends (cont)
- DOC: Fix typo so fetch is properly parsed by Cyril's converter
- BUG/MAJOR: http: fix breakage of "reqdeny" causing random crashes
- BUG/MEDIUM: stick-tables: fix breakage in table converters
- BUG/MEDIUM: dns: unbreak DNS resolver after header fix
- BUILD: fix build on Solaris 11
- CLEANUP: connection: fix double negation on memcmp()
- BUG/MEDIUM: stats: show servers state may show an servers from another backend
- BUG/MEDIUM: fix risk of segfault with "show tls-keys"
- BUG/MEDIUM: sticktables: segfault in some configuration error cases
- BUG/MEDIUM: lua: converters doesn't work
- BUG/MINOR: http: add-header: header name copied twice
- BUG/MEDIUM: http: add-header: buffer overwritten
- BUG/MINOR: ssl: fix potential memory leak in ssl_sock_load_dh_params()
- BUG/MINOR: http: url32+src should use the big endian version of url32
- BUG/MINOR: http: url32+src should check cli_conn before using it
- DOC: http: add documentation for url32 and url32+src
- BUG/MINOR: fix http-response set-log-level parsing error
- MINOR: systemd: Use variable for config and pidfile paths
- MINOR: systemd: Perform sanity check on config before reload (cherry picked from commit 68535bddf305fdd22f1449a039939b57245212e7)
- BUG/MINOR: init: always ensure that global.rlimit_nofile matches actual limits
- BUG/MINOR: init: ensure that FD limit is raised to the max allowed
- BUG/MEDIUM: external-checks: close all FDs right after the fork()
- BUG/MAJOR: external-checks: use asynchronous signal delivery
- BUG/MINOR: external-checks: do not unblock undesired signals
- BUILD/MEDIUM: rebuild everything when an include file is changed
- BUILD/MEDIUM: force a full rebuild if some build options change
- BUG/MINOR: srv-state: fix incorrect output of state file
- BUG/MINOR: ssl: close ssl key file on error
- BUG/MINOR: http: fix misleading error message for response captures
- BUG/BUILD: don't automatically run "make" on "make install"
- DOC: add missing doc for http-request deny [deny_status <status>]

Drop one patch included upstream.

(morr)